Material-testing machine



Nov. 30 1926. 1,608,804

R. R. Moo

MATERIAL TESTING MACHINE Filed 0G13. 5, 1925 INVENTOR @cH/m0 Q2/709MLATTORNEY Patented Nov. 30, 1926.

RICHARD RQ'MOORE, 0F DAYTON; OHIO.

Application `led October This invention relates to material testing`machines of the kind used in the testing ot' ,material specimens forfatigue, where they are subjected to alternating stresses ot' tension orcompression. For this purpose the specimen is subjected to a bendingload, and at the same time is power driven so as to be rotated, and thenumber of rotations may then be used together with the amount of thebending stresses for determining the ability of the material towithstand fatigue. The yprimary object of the invention is theiefore theprovision of amachine which should be capable of accurately determining5 the fatigue of the material and means of which the material may besubjected to the stresses desired.

A The invention concerns two housings, each of which rotatably supportsa journal and the ends of the specimen are attached firmly within atapered bore in the journals. The housings contain means for applying abending moment to the specimen and power means is supplied for drivingone of the journals so as to cause the rotation of the specimen. Thejournal housing on the driven side ott| the machine is supported on astandard which is mounted upon a base plate and this standard issupplied with a pair of opposed notches having vertical slide sideswhich slidingly support a pair of bearing slices, so that the bearingshoes are held to prevent lendwise movement ofthe housing but so as 'topermit the ready upward movement thereof, to enable its removal. Thesebearing shoes are held rotatably on ulcrumpins which are fixed to thehousing and which project outwardly from opposite sides thereof. Thisarrangement of mounting the 410 housing on the standard is one whichper- 4 mits readily mounting of the specimen in the journal, and whichis very effective in f reducing vibration chatter and its conse1 quentharmful effects which are likely to f produce stress of unknown value onthe specimen, in addition to those which are applied by the load.

. The journal housing on the tachometer side @fthe machine 01 that whichis farthest 5, 1925. Serial No. 60,505.

awa-y from the driven journal is supported upon a standard which ismounted upon the` base, on horizontal slides, which slidingly mount aplurality of bearing shoes which are held on the fulcrum pins of thishousing. Endwise movement of this housing is there- 5 fore permitted totake care of slight variatations in length of the specimen andpossibledeformation in length of the specimen under load.`

Each of the journal housings form a: mounting for a plain bearing withinwhich'v the journals are mounted for rotation. A slight endwise movementis permitted of the journals vwithin the bearings, so that a practicallyfrictionless endwise movenentis permitted to take care of slight changesof length of the specimen and so as no force will be exerted on thespecimen except that intended. The .ends of the specimens are heldwithin the journals by means of drawing-in bars, which extend throughthe bores of the journals and thread into the ends of the specimen.These drawing-in bars are tightened and held against the outer end ofthe journals so. that the tapers of the speci-- men are drawn tightly tothe mating tapers in the journals. The tightening means ou the ends ofthe drawing in bars provides a lock between the drawing in bar and theend of the journal to cause their simultaneous rotation, andwiththis-lock in place the tightening nut may' be tightened on the drawingin bar to draw the tapers up tight'- ly without causing any bending orstress on the specimen. This tightening nut is provided with a slotwithin which tits a head on a driving link, the other end of the drivinglink being provided with a` second driv-y ing head, which lits in a slotin a driven shaft. The driven. shaft is rotated by means of a suitablesource of power such as an electric` motor, so that the journals will berotated and the specimen subjected to a stress which is produced by loadapplying hangers mounted at a known distance Jfrom the ful- Crum pins.With the above objects in View therefore and With-other objects andadvantages which ards 1 and 2 are mounted the line 3-3 of Tandtightening nut.

Fig. 5 is a section on the line 5-5 of Fig. 4, and y Fig. 6 is anenlarged view of one end of a specimen.

ln the drawings, the pedestals or standor plate 31. llach oi thesestandards support a journal housing as shown at 3 and 4 which arepractically identical in construetion. Referring particularly tothe'journal housings, each housing is longtitudinally split in upper andlower halves 5 and G, attaehed together' by vertically extendingthrough-bolts as shown at" 7. ithin the housing is mounted a plainbearing 8 which rotatably supports a journal 9. This journal is hollowand the inner end of the journal is adapted to neatly receive the taperon the end of the specimen 10. The specimens are construeted all of thesame size and shape, andF each specimen has its ends provided withinside threads 11, which are engaged b 1 the drawing in bar 12 which isprovided with a threaded end to engage the threads 11. rl`his drawing inbar extends through the hollow journal and at its outer end is providedwith threads 13. Part of these threads are cut away so as to provide twoflattened opposite sides on the end o the drawing in bar as shown at 14in Fig. 5, and a setting lock 15 is adapted to slide along the end ofthe bar freely, being provided with projecting lugs 16. which fit incorresponding slots 17 in the end of the journal 9. lVhen this settinglock is in the position shown in Fig. 4, relative rotation or thespindle and the journal is prevented and the tightening nut 1S may bethreaded on the end of the. bar 12 so that the mating tapers on the endof the specimen and on thejournal will be drawn up tightly and thejournal and specimen thus fixed together. The tightening operation ofthe nut 18 will produce no bending or stress in the specimen lby 'reasonvof the setting lock 15 holding'the specimen to the journal againstrelative rotational movements.

The device as just mentioned forms a means by which the specimen may betightened in place and held to the journals, this tightening operationbeing done at the outer ends of the journal housings and away from theproximity of the specimen. Accidental striking of the specimen istherefore elimiupon a fixed base agree with the taper provided on theinner side of the journal and the middle portion of' the taper on thespecimen is relieved for a slight undercut as shown at Gli so that amore solid bearing between the journal and the specimen ends may beobtained. The drawing in bar 12 is provided with a bearing surface 19which neatly fits within the bore of the journal so that the drawing inbar is centered within the journal. the housings is provided with a pairof opposed fuleruinlpins 20 which are held in position on the housingbymeans of the bolts 7, which extend through the innerends ot' these pins.Each pin 20 is provided with a cylindrical bearing surface which ismounted within a coi-responding bearingl surface provided in a fulcrumpin shoe 2l. so that free relative rotation' is permitted and the shoe.The shoes areheld in place by means of the heads 22 providedon the pins.These heads 22 hold the. parts in assembled relation and permit thehousing to be -removed bodily without danger of the pins or shoesdropping oft, and vertical movement within a notch 28 in the top of eachside of the standard 1. These notches neatly support the bearing shoesso that endwise movement of the housing is prevented, and chatter andVibration is eliminated. At the same Each ot' j between the pin time afree pivotal movement of the housing horizontal slides 25 upon whichrest the two corresponding shoes 2l of this housing. Free endwisemovement of these shoes is permitted along the top slide of the pedestal2 to provide for slight variations in length ot the specimen or fordeformation of the specimen under load. Chatter and vibrationalmovements of the housings about a vertical axis is presented, however,in an efiicient manner n by the downwardly projecting fianges 24 whichengage on the vertical face on the support` as previously mentioned.

The journal 9 is constructed with an interna-l flange 26 which abutsagainst the adjacent portion of the bearing 8. This bearing 8 at thisportion is a babbitted Cil `ing for slight relative endwise movement,

An end plate 28 is secured to the inner end of the housing and itdesired may form a packing retainer. At the other end of the journal thelatter is supported by means of a babbitted brass bushing 29 which is apush tit within the aluminum housing 3. The journalis lubricated here byoil rings 30 which are of larger size than the journal and dip into theoil reservoir which is located in the space 31 below the journal. Thejournal itself is preferably of hardened steel, and the inner end of thejournal beafrs on the top thereof due to the manner in which the housingis supported. rl`he oil is supplied to the inner end of the journal froma hole drilled in the middle ot the bearing as indicated at 32. Thishole taps a longitudinal drain hole 33 in the lower part of the housing3. The drain hole is suppliedwith oil as it is located below the levelof the oil in the housing and oil is consequently supplied to the innerend of the journal, although the oil level in the housing, as may beseen from a sight glass 34 in the sides of the housing, is below thelevel of the journal, and oil is consequently prevented from ilowing outof the ends of the housing. The hydraulic head of .the oil should alwaysbe kept below the bottom of the oil outlet hole in the housing endplate. Oil slingers and felt wipers may be provided in the customarymanner if desired, The oil may be supplied to the housing through a hole35 in the top of the housing which is ordinarily closed bythe plug 36.Cooling fins as indicated at 37 are provided on the top and bottom ofthe housing.

Each of the housings is supplied with a load applying casting 38, see Fig'. 3. This casting 38 is provided with .the two upwardly extendingarms 39 which forma firm bifurcation extending around the lower side ofthe housing. ,These arms 39 have mounted therein the knife edges 40 and.these knife edges are adapted to be placed in the V shaped notchesprovided in plugs 4l' on the sides ofthe housing. These V shaped groovesare positioned a known distance away from the fulcrum point of thehousing, thus giving a known lever arm for the loa'd. The load may behung upon the casting 38 invany suitable manner; and for this purpose.the downwardl extending end of the casting 42 is provi edwith a hole 43to which the load may be attached, The stress upon the materia-l of thespecimen may thus be calculated since the amountJ ot the load is knownand the amount of the weight supplied on the casting 38 may-be changedif desired. Y

The two journals and the s ecimen are rotated in unison by means o anelectric motor 44 which drives a shaft 4 5. This shait'is provided witha slot 46 which loosely receives a cross pin or head 47 provided on adrive link 48. At its opposite end the link 48 is provided with a`second cross pin or head 49 which is loosely received in the cross slot50 in the end of the nut 18. A spring 51 is provided within a bore inthe shaft 45 and presses against the head 47 of the drive link. Thedrive link may therefore be readily removed by merely pressing the drivelink to the right, see F ig. 1, to compress the spring and permit theremova-l of the head4.) from its slot The drive link thus forms auniversal .connection between the drive shaft 45 and the spindle andspecimen so that no stresses or bending forces are exerted on thespecimen other than those exerted by reason of the rotational movementsof the shaft 45. The transmission of vibration from the motor prevented,

The rear end of the journal of the housing 4 is provided with acorresponding tightening nut 52, which is slotted .to receive` the crosshead 53 or a drive link 54, the other end of which is provided with ahead 55 mounted in a slot on the end of a shaft 56 which drives atachometer 57. This tachometer is su plied upon a pedestal 58 which isadjusta ly mounted` along a` slide 59 on the base 3. Adjustment ispermitted and fixed by means of a setting clamp G0 is thus- Thetachometer may thus be readily moved endwise to disengage it from thespindle within. Ithe housing 4. The tachometer forms a counter and givesan indicationv of the number of times the stress has beenv alternated onthe specimen.

The pedestal .2 is provided with a centrally located projecting. lipor'shelf 61 on which the housing 4 may fall after the specimen has beenbroken. Below the housing 3 is a throw out switch 62 which is operatedby means of a downwardly projecting lug 63 on the housing 3 when thespecimen is broken so `that the circuit through the motor 44 will bevinterrupted automatically by the weight ofthe housing atthe end of thetest.

llU

Theoperation of the machine and the i manner in which itis intended tobe used will now be understood from the preceding description. Thespecimen is first applied rigidly inposition by inserting its ends inthe corresponding ends of the two spindles,

the housing 4 being movedl to the left ,for this purpose. The twodrawing in bars are tightene tightening nuts, one at ay time andl t 1edrive links 48 -and 54`inserted in position,l the in position by drawingu `on thel f cally.

tions ot' the specimen countedby means ot" the tachometeror counter 58until the specimen breaks due to fatigue. 'When the break occurs the twohousings swing about their pivots freely and coine to rest on the shelt'(3l and the throw out switch 62. This throw out switch disconnects themotor automati- The swinging movement ofthe housings about their pivotsis permitted by reason ot' the particular type of loose connectionbetween the motor and the tachoiiietei and the two journal ends. Thelinks merely tall after they are released.

The use of the plain bearing as frictionless-support for the rotatablejournal is :i great improvement over the use of ball bearings` orsimilar trictionless type bearings. In a ball bearing the chatter andvibration entailed is harmful and disadvantageous on the specimen sincea stress is produced therein which cannot be calculated. It is veryimportant that the specimen should be subjected to no extraneousstresses other than these which can be accounted for and computed. Thisfreedom from vibration is also-a result of the wayin which the fulciuinpins ot' the housings are'supported upon a slide block or shoe and themanner in which shoes are mounted, so that the housing adjacent to thedriving motor is prevented from moving endwise or from oscillatinglabout a vertical axis by reason of the neat fit between the bearingshoes and the notches in the top of the pedestal support. Vibration isalso eliminated in the housing 4 by reason ot its mountingupon itsbearing shoes and the manner in which these bearing shoes are slidinglymounted ments and vibrations prevented withthe the second housing.

on the-standard 2, so that the housing 4 is permitted to move endwise,but other moveexception of the desired movement about the axis ot thesupporting tulcrum pins. It will be. understood that the twoliousings 3and 4 and the manner in which the load applying hangers are attachedthereto'f` are practically identical with the exception of the mountingprovided tor the fulcium pin shoes. The description which has been givenin detail for one of the housings will therefore apply equally to theother and it is not considered necessary to again describe I am aware.that various changes may be computed readily from lsaid specimen ing abase, a. standard on said base, a housing supported 'on said standardl'or pivotal movement, a journal in said housing, means for holding aspecimen in said journal, load applying means on said housing, a secondstandard on said base, a second journal housing on said second standard,

a second housing, means for attaching said specimen to said secondjournal, and means for rotating one of said journals to apply analternating stress on said specimen.

2. A material testing machine comprising a base, a standard on saidbase, a journal housing, a pair of fulcruin pins attached to saidhousing, pivotal movement on said fulcruin pins', there ard to neatlyh'old said bearing shoes,..a

journal in said housing, means for holding a" specimen inj said journal,load applying means on said housing,

3. A material testing machine comprisingv a base, 'a standard on saidbase, a journal housing, a journal therein, a pair of yfulcrum pinsattached to said housing, a bearbeing a pair 'of notches in said stand-`journal in said second journal sis a bearing shoe mounted fora secondjournal housing'on said base, a second journal in` ing shoe mounted forpivotal movement Von i said fulcruni pins, there being a pair ot notchesin said vstandard to neatly hold said bearing shoes, means for holding aspecimen in said journal, load applying means on said housing, a secondjournal housing, a second standard, afpair of fuleruntifpins on saidsecond journal-housing, a bearing shoe on each of said fulerum pins,ahorizontal slide on said secondstandard to support the bearing shoesonsaid second joui'- nal housing, a' second journal in said secondjournal'housing, means for attaching to said second journal, and meansfor rotating said lirst journal to apply an alternating stress on said.specimen.

4. A material testing machine comprising a base, a standard on saidbase, a journal housing supported on said standard for pivotal movement,a plain bearing in said journal housing, a hollow journal rotatablymounted in said plain bearing, a drawing in bar extending centrallythrough the journal and cooperating therewith for holding a specimen insaidjournal, load applying means on `said housing, a. second journalhousingl on said base, av plain bearing in said second journal housing,a second journal rotatably mounted within said second bearing, means forattaching said specimen to said second journal and means for rotatingone of said journals to apply an alternating stress` on said specimen.

5. A material testing machine as set forth in claim/t', said iirstmentioned journal housin'g'being held against endwise movement on saidstandard and said second journal housing having free sliding motion inrelation to said base.

6. A material testing machine as set forth in claim 2, said journalsVbeing hollow and provided with a tapered bore at one end adapted to-it' a' taper on a specimen.

7 A material testing machine comprising a standard, a journal housing, apair of ulcrum pins on said housing, a Abearing shoe pivotally mbuntedon each iulcrum pin, there being pair of notches on said standardinwhichlsaid shoes are neatly mounted, having vert-i al faces-for guidingsaid bearing shoes, a ",ollow' journal in said housing having a taperedbore at one end thereof adapted' to tit the end oi a specimen, a drawingin bar having a threaded end to engage and passing an end of saidspecimen through said journal, means movable endwise on said drawing inbar, and engaging said journal and a nut threaded on said drawing' inbar for rmly attaching said specimen and drawing in bar together, loadapplying means on said housing, a second journal housing aligned withsaid first mentioned journal housing, a second journal in said secondjournal housing, means for attaching said specimen to said secondjournal, and means for rotating said first 'ournal to apply analternating stress on' sai speci- 8. A material testing machine assetforth in 'claim 7, s aid journal housin being longitudinally split,means for attac ing the split portions together, and a plain bearingwith'- in each journalhousing' for rotatably sup- 5o' porting saidjournals therein.-

9. A material testing'machine' as set forth in claim 2, said loadapplying means comprising `a bifurcated hanger having knifeedges'thereon, there being a pair of V shaped grooves in said journalhousing'for the reception of said vflrnife edges.

. Y10. A material testing machine as` 'seti :forth in claim V1 togetherwith a plain bearlng in each of sald journal housings for rotatablysupporting said journals, saidjourf nals being permitted free endwisemovement in said bearin j 11. A material testmg machine as set forth inclaim et, said plain bearing having an .oil

bearing journal housing on said base, a second jour'- nal insaid secondjournal housing, a driving shaft having a slot in one.end,' a driving.bar having 'a head loosely fitting in said slot and having a secondheadfor drivingv said iirst journal, anda spring within said shaftpressing against said iirsthead where by said journal 1s rotated bv saidshaft .through a universal connection without' strain upon said journal.l

13. A material testing machine comprising a base, a standard on saidbase, a journal housing supported on said -standard for pivotal movementabout a horizontal axis, a'

journal in said housing, means operable at4 Athe end of the housingremote from the 1 specimen for holding a specimen in said journal, aload applying hangerv on: said housing, a second journal housing, -apedestal supported on said base for mounting said second journalhousing, a second journal in said housing, a second load applying hangeron said second housing,

nal, and operated at the endof the housing remote from the specimen, andmeans for rotatingone of said journals to` apply an alternatingstress-on said' specimen.`

1 4. A; material testing machine compris-iy ing a standard, a journalhousing, means for i mounting said housing on said standard, andcomprising ulcrumlpins, bearing shoes therefor and parallel guides forsaid bearing shoes, the ulcrum pins being provided on one of the partsand the guides on the other to mount the housing on the standard, plainin said housing, a hollow journal mounted therein and having a taperedbore .at one end adapted to t the end of a specimen, a drawing inbarextending thru said journal and having threads at one end for engagingthe specimen, means at the end of the rawing in bar remote from thespecimen engaging end for connecting the said bar rigidly to thejournal, a second journal .housing aligned with and adjacent to thelirst mentioned. housing, aY second journal therein, a second drawing in"bar to connect the second journal to a specimen, means forK eans foriattaching said specimen to said sec nd jourlll)

